Method for assembling a magnetic head assembly and magnetic disk drive using bonding balls connecting magnetic head terminals to wiring terminals

ABSTRACT

A method for assembling a magnetic head assembly with a slider and a magnetic head including forming, on a slider supporting member, a terminal connected to a magnetic head terminal. In addition, the method includes fixing a head slider on the slider supporting member so that the head terminal faces the terminal of the slider supporting member and contacting a conductive ball member to both of the head terminal and the terminal of the slider supporting member. Furthermore, the method includes pressing the ball member to bond the head terminal with the terminal of the slider supporting member so that the ball member connects the terminals electrically and mechanically.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a magnetic head assembly havinga thin-film or MR type magnetic head used for a magnetic disk drive.

[0003] 2. Description of the Related Art

[0004] Recently, in conventional magnetic disk drives, monolithic typemagnetic heads have been replaced with thin-film or MR type magneticheads.

[0005]FIG. 1A is an exploded view of an example of a magnetic headassembly (which can also be referred to as a magnetic head suspensionunit) having a thin-film type magnetic head used for the conventionalmagnetic disk drives. FIG. 1B is an exploded view of a part of themagnetic head suspension unit shown in FIG. 1A. In the presentspecification, the magnetic head suspension unit refers to an assemblyof a spring arm having a magnetic head mounted on an end of the springarm. The other end of the spring arm is adapted to be mounted on amember of a magnetic head positioning mechanism.

[0006] Referring now to FIG. 1A, one end (a base portion 1 a) of aspring arm (suspension) 1 formed of an elastic plate is mounted to amember of a magnetic head positioning mechanism (not shown in thefigure) via a plate-like spacer 2. A gimbal 3 is mounted on another end1 b of the spring arm 1. The gimbal 3 is mounted, as shown in FIG. 1B,on the spring arm 1 by means of laser welding at positions indicated byx. A core slider (head slider) 4 of a magnetic head h is mounted byadhesive on the gimbal 3.

[0007] Two magnetic head elements 5 are formed on a rear side surface ofthe magnetic head, the magnetic head elements 5 being connected by leadwires 6 which lead to a read wire 8 covered with an insulating tube 7fixed to the spring arm 1. The lead wire 8 is lead to arecording/reproducing circuit 9 shown in FIG. 2.

[0008] The spring arm 1 is slightly bent near the base portion 1 a sothat a bent portion 1 c is formed so as to generate a spring force.

[0009]FIG. 2 is an exploded view of a conventional magnetic disk drivein which two magnetic head suspension units shown in FIG. 1A are used.

[0010] Two magnetic head suspension units are mounted on a driving arm13 which pivots about an axis 12 so that a magnetic disk 10 accommodatedinside the magnetic head drive is sandwiched between two of the coresliders 4 mounted on the respective spring arms 1. Each of the coresliders 4 is pressed to a respective surface of the magnetic disk 10 bythe spring force generated by the bent portion 1 c.

[0011] When the magnetic disk 10 is rotated at a high speed, themagnetic heads h float, if the magnetic heads h are of the floatingtype, on the respective surface of the magnetic disk 10 due to an airflow generated by the rotation of the magnetic disk 10. If the magneticheads h are contact type magnetic heads, the magnetic heads h do notfloat, but instead slide on the respective surfaces of the magnetic disk10. The magnetic heads h are moved to respective target tracks on thesurfaces of the magnetic disk 10 by pivoting the spring arms about theaxis 12.

[0012]FIG. 3 is a perspective view of a thin-film type magnetic head.FIG. 4 is an enlarged cross sectional view of the thin-film typemagnetic head shown in FIG. 3 taken along a line A-A of FIG. 3.

[0013] The thin-film type magnetic head shown in FIG. 3 comprises theslider 4 and head elements 5. The head elements 5 are formed by means ofa film deposition technique and lithography. Terminals 15 a and 15 b forrecording/reproducing coils are provided near the head elements 5.

[0014] Each of the head elements 5 comprises a lower magnetic pole 16,an upper magnetic pole 17 and a thin-film coil 19 wound around aconnecting portion 18 between the lower magnetic pole 16 and the uppermagnetic pole 17. A gap insulating layer 20 is provided between thelower magnetic pole 16 and the upper magnetic pole 17 so that a gap Ghaving a predetermined width is formed between the two poles. The gap Gfaces the surface of the magnetic disk 10 to perform an magneticrecording/reproducing operation.

[0015] In the construction of the magnetic head suspension unit shown inFIG. 1 in which the lead wire 8 is covered with the insulating tube 7,the insulating tube 7 occupies a relatively large space to preventminiaturization of the magnetic disk drive. Additionally, the insulatingtube 7 makes an assembling operation difficult, particularly anautomated assembling operation. Further, there is a strong possibilitythat the lead wire 8 will pick up noises, resulting in degradation of anS/N ratio of a signal sent via the lead wire 8.

[0016] In order to eliminate the above-mentioned problems, a method forforming a signal transmitting line on a spring arm is suggested inJapanese Laid-Open Patent Application No.4-21918. In the method, asignal line is formed of a pattern of a conductive layer on aninsulating layer formed on the spring arm. However, the method has aproblem in that the signal transmitting line formed of the conductivelayer is easily damaged or broken during a process for forming the bentportion 1 c shown in FIG. 1A.

[0017] Japanese Laid-Open Patent Application No.4-111217 discloses amagnetic head suspension unit in which a flexible printed circuit boardis attached to a spring arm, and a portion of the flexible circuit boardcorresponding to the above of the spring arm bent portion is not adheredto the spring arm. Instead, in this construction, the portion of theflexible printed circuit board corresponding to the bent portion of thespring arm is free, and thus the there is no bending stress applied tothe flexible printed circuit board. However, this construction cannot beapplied to a highly miniaturized spring arm such as a spring arm havinga thickness of a few microns and a 4.6 mm width.

[0018] There is another problem in that ability of the insulating layers21 and 22 of the magnetic head element 5 t withstand dielectric voltageis very low because they each have a thickness of only 1 to a fewmicrons. Accordingly, if a relatively high voltage of about 100V or moreis applied between the thin-film coil 19 and the poles 16 and 17 due toa generation of static electricity, the insulating layers 21 and 22 maybe easily damaged due to electric discharge.

[0019] If the insulation between the thin-film coil 19 and the poles 16or 17 is damaged, an electric discharge may occur between the coreslider, which is made of a conductive material such as Al₂O₃TiC, and themagnetic poles 16 or 17, resulting in the gap G or the floating surfaceof the core slider 4 being damaged. Additionally, when the magnetic diskdrive is in operation, an electric discharge may occur between themagnetic disk 10 and the magnetic poles 16 or 17, resulting in themagnetic gap G being damaged. When the core slider 4 is damaged, thefloating characteristic of the magnetic head is deteriorated, whichcondition causes a generation of noises in the recording/reproducingsignal. If the magnetic head is a contact type head, the damaged surfaceof the magnetic head may scratch the magnetic disk 10.

[0020] Problems similar to the above-mentioned problems may occur whenthe core slider is miniaturized. That is, when the magnetic head isheated, the magnetic head tends to expand due to the thermal expansion,but a portion of the core slider attached to the gimbal or the springarm by adhesive cannot expand in accordance with the expansion of themagnetic head. This creates bending of the core slider, and thus thefloating characteristic of the magnetic head may be deteriorated.

SUMMARY OF THE INVENTION

[0021] It is a general object of the present invention to provide animproved and useful magnetic head assembly and a magnetic disk drivehaving such a magnetic head suspension unit in which the above-mentioneddisadvantages are eliminated.

[0022] A more specific object of the present invention is to provide amagnetic head assembly and a magnetic disk drive in which damaging of aconductive-pattern layer formed on a spring arm during a process ofbending the spring arm can be prevented.

[0023] Another object of the present invention is to provide a magnetichead assembly and a magnetic disk drive in which no insulation breakageoccurs due to generation of static electricity.

[0024] Another object of the present invention is to provide a magnetichead assembly and a magnetic disk drive in which thermal deformation ofa slider core is prevented.

[0025] In order to achieve the above-mentioned objects, there isprovided according to the present invention, a magnetic head assemblycomprising:

[0026] a slider on which a magnetic head is mounted, the slider havingterminals of the magnetic head;

[0027] a gimbal portion on which the slider is mounted;

[0028] terminals of wiring lines; and

[0029] balls bonding the terminals of the wiring lines and the terminalsof the slider.

[0030] The magnetic head assembly may be configured so that the ballsare made of gold.

[0031] The magnetic head assembly may be configured so that theterminals of the wiring lines are provided on the gimbal portion.

[0032] The magnetic head assembly may be configured so that the wiringlines are formed by a wiring pattern.

[0033] The magnetic head assembly may be configured so that the slideris provided on a surface of the gimbal portion on which the wiring linesare provided.

[0034] The magnetic head assembly may be configured so that the slideris provided on the gimbal portion so that the terminals of the wiringpattern and the terminals of the slider face each other in an orthogonalformation.

[0035] The magnetic head assembly may be configured so that the gimbalportion is a part of a suspension so that the gimbal portion isintegrally formed with the suspension.

[0036] The magnetic head assembly may be configured so that the wiringlines are formed by a wiring pattern formed on the suspension.

[0037] The magnetic head assembly may be configured so that the slideris provided on a surface of the gimbal portion on which the wiring linesare provided.

[0038] The magnetic head assembly may be configured so that the slideris provided on the gimbal portion so that the terminals of the wiringpattern and the terminals of the slider face each other in an orthogonalformation.

[0039] The above objects of the present invention are also achieved by amagnetic disk drive comprising:

[0040] an enclosure;

[0041] a magnetic disk provided in the enclosure;

[0042] a magnetic head assembly provided in the enclosure; and

[0043] an actuator to which the magnetic head suspension unit is fixed,the actuator moving the magnetic head assembly above the magnetic disk,wherein the magnetic head assembly is configured as described above.

BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The other objects, features and advantages of the presentinvention will be apparent from the following detailed description whenread in conjunction with the accompanying drawings, in which:

[0045]FIG. 1A is an exploded view of an example of a magnetic headassembly having the thin-film type magnetic head used for theconventional magnetic disk drives;

[0046]FIG. 1B is an exploded view of a part of the magnetic headassembly shown in FIG. 1A;

[0047]FIG. 2 is an exploded view of a conventional magnetic disk drivein which two magnetic head assemblies shown in FIG. 1A are used;

[0048]FIG. 3 is a perspective view of a thin-film type magnetic head;

[0049]FIG. 4 is an enlarged cross sectional view of the thin-film typemagnetic head shown in FIG. 3 taken along a line A-A of FIG. 3;

[0050]FIG. 5A is a perspective view of a first embodiment of a magnetichead assembly according to the present invention;

[0051]FIG. 5B is an enlarged cross sectional view taken along a line b-bof FIG. 5A;

[0052]FIG. 6A is a perspective view of the spring arm shown in FIG. 5Ain a state where a magnetic head has not been mounted on a gimbal;

[0053]FIG. 6B is an illustration showing a process for formingconductive-pattern layers on the spring arm;

[0054]FIGS. 7A through 7C are illustrations showing a process forbending the bent portions shown in FIG. 6A;

[0055]FIG. 8A is a perspective view of a second embodiment of a magnetichead assembly according to the present invention;

[0056]FIG. 8B is an enlarged partial cross sectional view taken along aline b-b of FIG. 8A;

[0057]FIG. 8C is an enlarged partial cross sectional view taken along aline c-c of FIG. 8A;

[0058]FIG. 8D is a partial cross sectional view of a variation of thespring arm shown in FIG. 8A;

[0059]FIG. 9A is a perspective view of a third embodiment of a magnetichead assembly according to the present invention;

[0060]FIG. 9B is a cross sectional view taken along a line b-b of FIG.9A;

[0061]FIG. 10 is a perspective view of a fourth embodiment of a magnetichead assembly according to the present invention;

[0062]FIG. 11A is a perspective view of a fifth embodiment of a magnetichead assembly according to the present invention;

[0063]FIG. 11B is an enlarged partial cross sectional view taken along aline b-b of FIG. 11A.

[0064]FIG. 12A is a perspective view of a sixth embodiment of a magnetichead assembly according to the preset invention;

[0065]FIG. 12B is an enlarged partial cross sectional view taken along aline b-b of FIG. 12A;

[0066]FIG. 12C is an enlarged partial cross sectional view taken along aline c-c of FIG. 12C;

[0067]FIG. 13A is a perspective view of a seventh embodiment of amagnetic head assembly according to the present invention;

[0068]FIG. 13B is a variation of the embodiment shown in FIG. 13A;

[0069]FIG. 14 is a perspective view of an eighth embodiment of amagnetic head assembly according to the present invention;

[0070]FIG. 15A is a perspective view of the magnetic head shown in FIG.14;

[0071]FIG. 15B is a cross sectional view taken along a line b-b of FIG.15A;

[0072]FIG. 16 is an exploded view of an essential part of a ninthembodiment of a magnetic head assembly according to the presentinvention;

[0073]FIG. 17 is an exploded view of an essential part of a variation ofthe ninth embodiment shown in FIG. 16;

[0074]FIG. 18 is a perspective view of an essential part of a tenthembodiment of a magnetic head assembly according to the presentinvention;

[0075]FIG. 19 is an exploded view of an eleventh embodiment of amagnetic head assembly according to the present invention;

[0076]FIG. 20A is a perspective view of a spring arm of a twelfthembodiment of a magnetic head assembly according to the presentinvention;

[0077]FIG. 20B is an enlarged cross sectional view of a mountingstructure of the core slider shown in FIG. 20A;

[0078]FIGS. 21A through 21F are illustrations of variations of the holeshown in FIG. 20A; and

[0079]FIG. 22A is a perspective view of a spring arm of a thirteenthembodiment of a magnetic head assembly according to the presentinvention;

[0080]FIG. 22B is an enlarged cross sectional view of a mountingstructure of the core slider shown in FIG. 22A;

[0081]FIG. 22C is an enlarged cross sectional view showing a variationof the mounting structure shown in FIG. 22B;

[0082]FIG. 23 is a perspective view of a magnetic head assemblyaccording to a fourteenth embodiment of the present invention;

[0083]FIG. 24 is a plan view of a 3.5-inch magnetic disk drive to whichthe magnetic head assembly shown in FIG. 23 is applied;

[0084]FIG. 25 is a perspective view of a first-order bend state of asuspension shown in FIG. 23;

[0085]FIG. 26 is a perspective view of a first-order twist state of thesuspension shown in FIG. 23;

[0086]FIG. 27 is a perspective view of the upper side of the magnetichead assembly shown in FIG. 23;

[0087]FIG. 28 is a side view of the magnetic head assembly shown in FIG.23;

[0088]FIG. 29 is a perspective view of a magnetic head assemblyaccording to a fifteenth embodiment of the present invention;

[0089]FIG. 30 is a perspective view of a magnetic head assemblyaccording to a sixteenth embodiment of the present invention;

[0090]FIG. 31 is a perspective view of a magnetic head assemblyaccording to the twelfth embodiment of the present invention;

[0091]FIG. 32 is a side view of the mechanism shown in FIG. 31;

[0092]FIG. 33 is a perspective view of a magnetic head assemblyaccording to an eighteenth embodiment of the present invention;

[0093]FIG. 34 is a perspective view of a magnetic head assemblyaccording to a nineteenth embodiment of the present invention;

[0094]FIG. 35 is a plan view of a free-end part of a suspension shown inFIG. 34;

[0095]FIG. 36 is a sectional-view taken along a line XIV-XIV shown inFIG. 34;

[0096]FIG. 37 is a perspective view of a magnetic head slider shown inFIG. 34;

[0097]FIG. 38 is a flowchart of a production process for the suspensionshown in FIG. 34;

[0098]FIG. 39 is a plan view of a plate obtained after an etching stepshown in FIG. 38 is carried out;

[0099]FIG. 40 is a flowchart of another production process for thesuspension shown in FIG. 34;

[0100]FIG. 41 is a perspective view of a variation of the nineteenthembodiment of the present invention;

[0101]FIG. 42 is a perspective view of a magnetic head assemblyaccording to a twelfth embodiment of the present invention;

[0102]FIG. 43 is a plan view of a magnetic disk drive to which themagnetic head assembly shown in FIG. 42 is applied;

[0103]FIGS. 44A and 44B are respectively plan and side views of themagnetic head assembly shown in FIG. 42;

[0104]FIG. 45 is a side view of a state observed when the magnetic headassembly shown in FIG. 42 is provided in the magnetic disk drive;

[0105]FIG. 46 is an emphasized view of the state in FIG. 45;

[0106]FIG. 47 is a side view of a first-order bend state of a suspensionused in the twelfth embodiment of the present invention;

[0107]FIG. 48 is a side view of a first-order twist state of thesuspension used in the twelfth embodiment of the present invention;

[0108]FIG. 49 is a plan view of a first variation of a gimbal of thesuspension used in the twelfth embodiment of the present invention;

[0109]FIG. 50 is a plan view of a second variation of the gimbal of thesuspension used in the twelfth embodiment of the present invention;

[0110]FIG. 51 is a plan view of a third variation of the gimbal of thesuspension used in the twelfth embodiment of the present invention;

[0111]FIG. 52 is a plan view of a fourth variation of the gimbal of thesuspension used in the twelfth embodiment of the present invention;

[0112]FIG. 53 is a plan view of a fifth variation of the gimbal of thesuspension used in the twelfth embodiment of the present invention; and

[0113]FIG. 54 is a side view of a variation of the twelfth embodiment ofthe present invention.

[0114]FIG. 55 is a top view of another embodiment of a magnetic diskapparatus of the present invention;

[0115]FIG. 56 is a cross section of the magnetic disk apparatus in FIG.55;

[0116]FIG. 57 is a top view of an actuator in FIG. 55;

[0117]FIG. 58 is a perspective view of a magnetic head assemblyaccording to a further embodiment of the present invention;

[0118]FIG. 59 illustrates another connecting mechanism of the magnetichead assembly in FIG. 58;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0119] A description will now be given, with reference to FIGS. 5A and5B, of a first embodiment of the present invention. FIG. 5A is aperspective view of a first embodiment of a magnetic head assemblyaccording to the present invention, and FIG. 5B is an enlarged crosssectional view taken along a line b-b of FIG. 5A. Hereinafter, themagnetic head assembly is also referred to a magnetic head suspensionunit or merely suspension unit. In FIGS. 5A and 5B, parts that are thesame as the parts shown in FIG. 1A are given the same referencenumerals, and descriptions thereof will be omitted.

[0120] The first embodiment according to the present invention comprisesthe spring arm 1 and the slider core 4 of the magnetic head. A gimbal 24supported by bridge portions 23 a and 23 b is formed on the end 1 b ofthe spring arm 1. The core slider (head slider) 4 of the magnetic headis mounted on the gimbal 24 by an adhesive which has an insulationeffect and can be an insulation adhesive or an adhesive containing aninsulator. The insulation adhesive is an insulator in which theinsulator itself has the insulation effect.

[0121] The base portion (attachment portion) 1 a of the spring arm 1 isfixed to a member of a magnetic head positioning mechanism.Conductive-pattern layers 25 run from the base portion la to the gimbal24 so as to transmit signals to/from the magnetic head.

[0122]FIG. 6A is a perspective view of the spring arm 1 shown in FIG. 5Ain a state where the magnetic head has not been mounted on the gimbal24. In FIG. 6A, a portion of the core slider 4 is also shown to explainelectrical connection between the magnetic head and theconductive-pattern layers 25. A pad 25 a is formed at the end of each ofthe two conductive-pattern layers 25. The core slider of the magnetichead is also provided with pads 26. When the core slider 4 is mounted onthe gimbal 24, the pads 26 make contact with the respective pads 25 a.The pads 26 and the pads 25 a are then soldered together to assure anelectric connection. It should be noted that the core slider 4 in FIG.6A is viewed from a direction indicated by an arrow B of FIG. 5A.

[0123] The conductive-pattern layers 25 on the spring arm 1 are formedby a process shown in FIG. 6B. As shown by FIG. 6B-2, an insulatinglayer 27 is formed on the spring arm 1 by applying a polyimide resinover the spring arm 1 made of stainless steel. The thickness of thespring arm 1 is about 25 μm, and the thickness of the insulating layer27 is 3-4μm. A base layer 28 is then formed on the insulating layer 27,as shown in FIG. 6B-3, by sputtering copper (Cu) onto the insulatinglayer 27. The base layer 28 may instead be formed by vapor deposition orchemical plating.

[0124] Using the base layer 28, electro plating is performed to form acopper layer 29 on the base layer 28, as shown in FIG. 6B-4. As shown inFIG. 6B-5, the base layer 28 and the copper layer 29 are etched so thatthe conductive-pattern layers 25 remain on the spring arm 1. Lastly,polyimide resin is applied over the conductive-pattern layers 25 so asto form an insulating film 30 which covers the conductive-pattern layers25 to protect them.

[0125] If a bending process is performed by applying a pressing force tothe conductive-pattern layers 25 formed on the spring arm 1, theconductive-pattern layers 25 may be damaged or destroyed. In order toeliminate this problem, in the first embodiment of the presentinvention, rectangular holes 31 a and 31 b are formed on the spring arm1, as shown in FIG. 5A, on either side of the conductive-pattern layers25. The rectangular holes 31 a and 31 b separate a portion of the springarm 1, on which the conductive-pattern layers 25 are formed, from bentportions 33 a and 33 b to which a pressing force is applied to bend thespring arm 1. The rectangular holes 31 a and 31 b may instead be slits32 a and 32 b as shown in FIG. 6A.

[0126]FIGS. 7A through 7C are illustrations showing a process forbending the bent portions 33 a and 33 b. As shown in FIG. 7A, first aroller 34 having larger diameter portions 35 a and 35 b is prepared. Thelarger diameter portions 35 a and 35 b bends the corresponding bentportions 33 a and 33 b. The bent portions 33 a and 33 b, which areformed as an elastic portion R generating an elastic force, of springarm 1 are placed on a rubber table 36. The roller 34 is then rolled, asshown in FIG. 7B, on the bent portion 33 a and 33 b while it is beingpressed. As a result, only the bent portions 33 a and 33 b arepermanently deformed into an arc-like shape, while the portion of thespring arm 1, on which portion the conductive-pattern layers are formed,between the bent portions 33 a and 33 b is elastically deformed.

[0127] According to the present embodiment, the roller 34 is not pressedon the portion where the conductive-pattern layers 25 have been formed,and thus no damage to the conductive-pattern layers 25 occurs.

[0128] A description will now be given, with reference to FIGS. 8Athrough 8D, of a second embodiment according to the present invention.FIG. 8A is a perspective view of a second embodiment of a magnetic headsuspension unit according to the present invention; FIG. 8B is anenlarged partial cross sectional view taken along a line b-b of FIG. 8A;FIG. 8C is an enlarged partial cross sectional view taken along a linec-c of FIG. 8A. FIG. 8D is a partial cross sectional view of a variationof the spring arm shown in FIG. 8A.

[0129] In the present embodiment, a recessed portion 39 is formed in theelastic portion R where an elastic force is generated. Theconductive-pattern layers 25 are formed in the recessed portion 39. Therecessed portion 39 covers an entire length C of the elastic portion Rand a width B so as to cover the portions of the conductive-patternlayers 25 located in the elastic portion R of the spring arm 1.

[0130] In this embodiment, a portion of the insulating layer 27 shown inFIG. 6B-2 is formed also inside the recessed portion 39. The base layer28 and the copper layer 29 are then formed on the entire surface of theinsulating layer 27 including the portion thereof inside the recessedportion 39 so as to form the conductive-pattern layers 25. Lastly, theinsulating layer 30 is formed on the conductive-pattern layers 25 sothat a top surface of the insulating layer 30 located inside therecessed portion 39 is below the surface of the spring arm 1 as shown inFIG. 8B.

[0131] In the present invention, since the portion inside the recessedportion 39 do not come into contact with the roller for forming the bentportions even though the roller has a straight cylindrical surface, nodamage occurs to the conductive-pattern layers 25, the same as in thecase of the above-mentioned first embodiment.

[0132] Although in the above embodiment the recessed portion 39 isformed by means of etching, the recessed portion 39 may instead beformed by means of press forming as shown in FIG. 8D. By using pressforming, the recessed portion 39 can be formed even if the thickness ofthe spring arm 1 is very slight or the total thickness of the insulatinglayers 27 and 30 and the conductive-pattern layers 25 is great. Therecessed portion 39 may be formed so that an entire length 25L ofstraight portions of the conductive-pattern layers 25 is embedded in therecessed portion 39.

[0133] A description will now be given, with reference to FIGS. 9A and9B, of a third embodiment according to the present invention. FIG. 9A isa perspective view of a third embodiment of a magnetic head suspensionunit according to the present invention; FIG. 9B is a cross sectionalview taken along a line b-b of FIG. 9A.

[0134] In the present embodiment, portions 25 r of theconductive-pattern layers 25, corresponding to the elastic portion Rwhich generates an elastic force, are wider than other portions of theconductive-pattern layers 25. That is, a width C₁ of each of the portion25 r of the conductive-pattern layers 25 within the elastic portion R iswidened over a length L corresponding to the elastic portion R. Thetotal thickness of the conductive-pattern layers 25 and insulatinglayers 27 and 30 is uniform over the entire width of the widenedportions 25 r of the conductive-pattern layers 25. A roller 35 having astraight cylindrical surface is pressed over the entire width of theelastic portion R so as to bend the elastic portion R.

[0135] If the conductive-pattern layers 25 or the insulating layer 30 inthe elastic portion R are protruded as shown in FIG. 6B, the pressingforce exerted by the roller 35 is concentrated onto theconductive-pattern layers 25. However, in the present embodiment, thepressing force is dispersed onto the entire width of the widenedconductive-pattern layers 25, and thus damage or breakage of theconductive-pattern layers 25 is prevented. Additionally, even if damagesuch as a cracking of portions of the conductive-pattern layers 25occurs, other portions of the layers 25 which are not damaged, resultingin reliable electric continuity. In the present embodiment, the width c1of each of the portion 25 r of the conductive-pattern layers 25 is 2.0mm, and the length L is 1.5 mm.

[0136] A description will now be given, with reference to FIG. 10, of afourth embodiment according to the present invention. FIG. 10 is aperspective view of a fourth embodiment of a magnetic head suspensionunit according to the present invention.

[0137] In the present embodiment, zigzagging conductive-pattern portions25 z of the conductive-pattern layers 25 within the elastic portion Rare formed to extend in a direction oblique to a direction in whichother portions of the conductive-pattern layers 25 extend. Preferably,U-turn portions 25 c are formed with a width greater than otherportions. As a result, in the present embodiment, pressing force isdispersed over the contacting area of the roller to be pressed, thusreducing damaging and breakage of the conductive-pattern layers 25.

[0138] A description will now be given, with reference to FIGS. 11A and11B, of a fifth embodiment of the present invention. FIG. 11A is aperspective view of a fourth embodiment of a magnetic head suspensionunit according to the present invention; FIG. 11B is an enlarged partialcross sectional view taken along a line b-b of FIG. 11A.

[0139] In the present embodiment, a plurality of dummy patterns 25 d areformed within the elastic portion R. The dummy patterns 25 d have thesame construction as the conductive-pattern layers 25. When the elasticportion R is pressed by the roller 35 as shown in FIG. 11B, the pressingforce is dispersed onto the dummy patterns 25 d, and thus damage andbreakage of the conductive-pattern layers 25 is prevented unlike in thecase of the conventional conductive-pattern layers in which the pressingforce is concentrated onto the conductive-pattern layers.

[0140]FIG. 12A is a perspective view of a sixth embodiment of a magnetichead suspension unit according to the preset invention; FIG. 12B is anenlarged partial cross sectional view taken along a line b-b of FIG.12A; FIG. 12C is an enlarged partial cross sectional view taken along aline c-c of FIG. 12C. In the sixth embodiment, a protecting layer isformed over portions of the conductive-pattern layers 25 in the elasticportion R. The protecting layer comprises a conducting layer 37 and aninsulating layer 38.

[0141] In order to make the present embodiment, a copper base layer isformed on the insulating layer 30 in the process shown in FIG. 6B-3-6.The conductive layer 37 made of copper is then formed by means ofelectro plating, and the layer 37 is patterned. Polyimide resin iscoated over the conductive layer 37 so as to form the insulating layer38. Preferably, the insulating layer 30 formed over theconductive-pattern layers 25 is formed with a relatively great thicknessso that the insulating layer 30 can be flattened and smoothed by meansof surface polishing. The conductive layer 37 has a relatively largewidth B to cover the conductive-pattern layers 25, and has a length Cwhich covers the length of the elastic portion R as shown in FIG. 12A.

[0142] In the present embodiment, the roller 35 exerts a pressing forceonto the conductive layer 37 which has a relatively high strength, andthus the pressing force is uniformly dispersed onto the conductive layer37. Accordingly, damage to the conductive-pattern layers 25 is preventedwhen the spring arm 1 is bent by the roller 35.

[0143]FIG. 13A is a perspective view of a seventh embodiment of amagnetic head suspension unit according to the present invention. In theseventh embodiment, extra conductive-pattern layers 25 s are formed. Theextra conductive-pattern layers 25 s are formed along each of theconductive layers 25. Both ends of each of the additionalconductive-pattern layers 25 s are connected to the ends of therespective conductive-pattern layers 25 at corresponding connectionparts 40 and 41. Accordingly, if one of the conductive-pattern layers 25is damaged to lose continuity, the corresponding extraconductive-pattern layer 25 s serves the same function as the damagedconductive-pattern layer 25. Therefore, a reliable connection can berealized.

[0144]FIG. 13B is a variation of the seventh embodiment according to thepresent invention. In this variation, each of the conductive-patternlayers 25 has two paths along the straight portion thereof within theelastic portion R. One of the paths serves as the extraconductive-pattern layer 25 s.

[0145] In all the above-mentioned embodiments and variations thereof,although the bent portions are formed by a press method using a roller,other method using a mold press or laser may be used.

[0146] Since the spring arm 1 according to the above-mentionedembodiments is mounted on a member of the magnetic head positioningmechanism, as shown in FIG. 2, the magnetic disk drive can reliablytransmit recording/reproducing signals through the spring arm.

[0147] A description will now be given, with reference to FIG. 14 andFIG. 15A and 15B, of an eighth embodiment according to the presentinvention. FIG. 14 is a perspective view of the eighth embodiment of amagnetic head suspension unit according to the present invention. InFIG. 14, parts that are the same as the parts shown in FIG. 1A are giventhe same reference numerals, and descriptions thereof will be omitted.FIG. 15A is a perspective view of the magnetic head h shown in FIG. 14;FIG. 15B is a cross sectional view taken along a line b-b of FIG. 15A.

[0148] In the eighth embodiment according to the present invention, thecore slider 4 is mounted on the gimbal 3 by adhesive 42 having a highinsulating effect. The core slider 4 may instead be directly mounted onthe end 1 b of the spring arm 1. Although, in the prior art, the coreslider is also mounted by adhesive having an insulating effect, theelectric resistance between the core slider 4 and the gimbal 3 is lowbecause the adhesive layer is very thin. Accordingly, the core slider 4may be at the same potential, that is a ground potential, as the springarm 1 because the spring arm 1 is grounded. If a high voltage staticelectricity is generated in the thin-film coil of the magnetic headelement 5, the insulating layer between the thin-film coil and themagnetic pole is damaged, resulting in electric discharge between thethin-film coil and the core slider.

[0149] In the eighth embodiment, in order to obtain a high resistancebetween the core slider and the gimbal 3, a thick layer of the adhesive42 is provided. It is preferable that the adhesive 42 be a UV cure resin(ultra-violet cure type adhesive). Alternatively, epoxy resin may beused. In the present embodiment, as shown in FIG. 15A, the adhesive 42comprises an insulating material powder 42 b mixed in adhesive medium 42a. Accordingly, the adhesive 42 can have a high electric resistance, andis formed with a relatively great thickness, and thus the insulationbetween the core slider 4 and the gimbal 3 is improved.

[0150]FIG. 16 is an exploded view of an essential part of a ninthembodiment of a magnetic head suspension unit according to the presentinvention. In the ninth embodiment, the core slider 4 is mounted on thegimbal 3 or the end 1 b of the spring arm 1 via an insulator 43. In thepresent embodiment, the insulator 43 is formed by applying insulatingresin such as a photoresist onto a surface of the core slider 4. Thecore slider is mounted on the gimbal 3 by applying adhesive 44 onto theinsulator 43. Alternatively, as shown in FIG. 17, the insulator 43 maybe applied onto a mounting surface of the gimbal 3.

[0151]FIG. 18 is a perspective view of an essential part of a tenthembodiment according to the present invention. In FIG. 18, a magnetichead comprising the magnetic head elements 5 and a core slider 4 i isshown. Unlike the conventional magnetic head, the core slider 4 i ismade of an insulating material such as SiO₂. Accordingly, the dischargeas described in relation to the conventional magnetic head can beeliminated.

[0152]FIG. 19 is an exploded view of an eleventh embodiment of amagnetic head suspension unit according to the present invention. I thepresent embodiment, the magnetic head suspension unit is mounted on adriving arm 13 of the magnetic head driving mechanism via an insulatingmember 45. The insulating member has screw holes 46 into which screwsfor fastening the magnetic head suspension unit to the driving arm 13are inserted. The screws are made of synthetic resin or metal screwscovered with synthetic resin. Accordingly, the spring arm 1 is insulatedfrom the driving arm 13, which may be grounded. Alternatively, thespacer 2 may be made of an insulating material.

[0153] In the present embodiment, since the spring arm is notelectrically connected to the driving arm 13, which may be grounded, noelectric discharge occurs between the core slider 4 and the magneticpole.

[0154]FIG. 20A is a perspective view of a spring arm of a twelfthembodiment of a magnetic head suspension unit according to the presentinvention; FIG. 20B is an enlarged cross sectional view showing amounting structure of the core slider shown in FIG. 20A. In the presentembodiment, a gimbal 24 formed on the spring arm 1 has a hole 47 in thecenter thereof. As shown in FIG. 20B, the core slider 4 is mounted onthe gimbal 24 by adhesive 48 so that the hole 47 is filled with theadhesive 48. Since the hole is formed in the gimbal 24, the gimbal canbe easily bent, if bending stress is applied to the gimbal 24 due to adifference in thermal expansion between the core slider and the gimbal24. Accordingly, bending stress applied to the core slider 4 is reducedsince the gimbal 24 is bent instead of the core slider 4. This featureis important when a thin and miniaturized core slider is used.

[0155] Variations of the hole 47 are shown in FIGS. 21A through 21F. Aplurality of holes 47 may be provided, and each hole may have arectangular shape.

[0156] In the present embodiment, the hole 47 is filled with a part ofthe adhesive applied between the core slider 4 and the gimbal 24, sothat the strength of the adhesion between the core slider 4 and thegimbal 24 is increased. Additionally, if the UV cure resin is used, anultra-violet beam can be irradiated through the hole 47, whicheffectively cures the UV cure resin, and thus the strength of the curedUV cure resin can be improved.

[0157] It should be noted that although the gimbal 24 is integrallyformed with the spring arm 1, the gimbal 24 may be formed separatelyfrom the spring arm 1; that is, it may be fixed to the spring arm 1 bymeans of welding described in regard to the conventional magnetic headsuspension unit shown in FIG. 1B.

[0158]FIG. 22A is a perspective view of a spring arm of a thirteenthembodiment of a magnetic head suspension unit according to the presentinvention; FIG. 22B is an enlarged cross sectional view of a mountingstructure of the core slider shown in FIG. 22A; FIG. 22C is an enlargedcross sectional view showing a variation of the mounting structure shownin FIG. 22B. In the present embodiment, an opening 49 is provided in thegimbal 24, into which opening the core slider is inserted. The opening49 is slightly larger than the outer dimension of the core slider 4.

[0159] The core slider 4 is mounted in a state where side faces of theslider core 4 is fixed, as shown in FIG. 22B, by adhesive 50 to theouter edge of the opening 49. Alternatively, as shown in FIG. 22C, thecore slider 4 may be formed to have a step in its side surface so thatdimension L₂ is larger than dimension L₁. The dimension of the openingis determined to be a value between L₁ and L₂. The adhesive such as UVcure resin is applied to the outer edge of the opening after the coreslider 4 is inserted into the opening 49. An ultra-violet beam is, thenirradiated from a direction indicated by an arrow in FIG. 22C so as tocure the UV cure resin.

[0160] In the present embodiment, since the core slider 4 is supportedat the side surfaces thereof, stress generated by thermal expansion ofthe gimbal 24 is lessened. Accordingly, deformation of the core slider 4due to the thermal expansion of the gimbal can be efficiently prevented.

[0161] It should be noted that the magnetic heads shown in FIGS. 20A and22A are formed with an MR element formed by means of thin-filmtechnology. Thin-film type magnetic head elements are formed on the MRelement. However, the present invention is not limited to the specificmagnetic head, and a conventional thin-film type magnetic head or amonolithic type magnetic head may be used.

[0162] A description will now be given, with reference to FIG. 23, of amagnetic head suspension unit 120 according to a fourteenth embodimentof the present invention.

[0163]FIG. 24 shows a 3.5-inch type magnetic disk drive 1220 to whichthe magnetic head suspension unit 120 is applied. The magnetic diskdrive 1220 has an enclosure 1221 in which a 3.5-inch magnetic disk 1222,a head positioning actuator 1223 and other parts are housed.

[0164] A suspension (load beam) 121 made of stainless steel is fixed toan arm 122 of the actuator 223. The suspension 121 has a curved bentportion 123 generating elasticity. In this regard, the curved portion123 of the suspension 121 is also referred to as an elastic portion 123in the following description. The suspension 121 has a stiffness portion24 extending from the elastic portion 123, and ribs 121 a. The elasticportion 123 provides a magnetic head slider (core slider) 135 with aload in a direction in which the magnetic head slider 135 moves andcomes into contact with a magnetic disk 1222. The suspension 121 has auniform thickness of, for example, approximately 25 μm, which is equalto one-third of the thickness of a suspension of a 3380-type (IBM) headsuspension unit.

[0165] It is desirable that the width W1 of the suspension 121 is madeas small as possible, desirably 4 mm or less. This is because theresonance frequency of vibration of the suspension 121 is prevented fromlowering.

[0166] A gimbal 125 is integrally formed in the suspension 121 so thatthe suspension 121 and the gimbal has a one-piece construction whichuses a plate. The gimbal 125 includes a pair of C-shaped openings 126and 126 facing each other in the longitudinal direction of thesuspension 121. Two slits 128 and 129 are formed in the suspension 121along respective sides of the suspension 121.

[0167] The gimbal 125 includes a magnetic slider fixing portion 130, afirst pair of beam portions 131 and 132, and a second pair of beamportions 133 and 134. The magnetic head slider fixing portion 130 haslarge surface dimensions enough to fix the magnetic head slider 135thereon, and has the same dimensions as the magnetic head slider 135(a=1.6 mm, b=2.0 mm). However, it is possible for the slider fixingportion 130 to have an area less than the magnetic head slider 135 whena sufficient adhesive strength can be obtained.

[0168] The magnetic head slider 135 is a light weight structure typeslider, which has been proposed in Japanese Patent Laid-Open ApplicationNo. 4-228157. The proposed slider has a flat back surface opposite to adisk facing surface. The flat back surface of the slider is fixed to thefixing portion 130 by means of an adhesive, which can be an insulationadhesive or an adhesive including an insulator (for example, insulatorpower). In this case, the slider 135 is located so that the centerthereof corresponds to the center of the fixing portion 130. It is alsopossible to use other types of sliders.

[0169] The beam portions 131 and 132 extend outwardly from therespective sides of the fixing portion 130 along a line (suspensionwidth direction line) 138, which passes through the center of the fixingportion 130 (the above center is also the center of the slider 135), andcrosses a longitudinal center line 137 of the suspension 121 at a rightangle. Each of the beam portions 131 and 132 has a length 11.

[0170] The beam portion 133 extends from the beam portion 131 towardsthe respective sides of the beam portion 131 so that the beam portion133 crosses the beam portion 131 at a right angle and extends parallelto the line 137. Similarly, the beam portion 134 extends from the beamportion 132 towards the respective sides of the beam portion 132 so thatthe beam portion 134 crosses the beam portion 132 at a right angle andextends in parallel with the line 137. The beam portion 133 is joined toportions 140 and 141 of the suspension 121 in the periphery of thegimbal 125. Similarly, the beam portion 134 is joined to portions 142and 143 of the suspension 121 in the periphery of the gimbal 125. Inother words, the beam portion 133 extends from the portions 140 and 141of the gimbal 125, and the beam portion 134 extends from the portions142 and 143 of the gimbal 125. The distance between the center of thebeam portion 133 and one of the two ends thereof is 1₂. Similarly, thedistance between the center of the beam portion 134 and one of the twoends thereof is also 1₂.

[0171] The beam portion 133 and the beam portion 131 form a T-shapedbeam 139A. Similarly, the beam portion 134 and the beam portion 132 forma T-shaped beam 139B. The beam portions 131, 132, 133 and 134 form anH-shaped beam. It will be noted that the fixing portion 130, the firstpair of beams 131 and 132, and the second pair of beams 133 and 134 areportions of the suspension 121.

[0172] The length 1₁ of the first pair of beams 131 and 132 is limitedby the width W1 of the suspension 121. As the width W1 of the suspension121 is increased, the resonance frequency of a bend and twist of thesuspension 121 becomes lower, and the flying characteristics of theslider 135 are degraded. For these reasons, the width W1 cannot beincreased. However, according to the fourteenth embodiment of thepresent invention, it is possible to increase the length 1₂ of thesecond pair of beams 133 and 134 without being limited by the width W1of the suspension 121. The second pair of beams 133 and 134 is formed sothat 1₂ >l ₁. That is, each of the T-shaped beams 39A and 39B has a legportion and an arm portion longer than the leg portion.

[0173] When a waviness of the magnetic disk being rotated is present ordust adheres to the magnetic disk, the magnetic head slider 135 isrotated in a pitching direction indicated by an arrow 144 in a state inwhich the first pair of beams 131 and 132 and the second pair of beams133 and 134 are bent. At this time, a twist deformation occurs in thefirst pair of beams 131 and 132 of the gimbal 125, and a benddeformation occurs in the second pair of beams 133 and 134.

[0174] As indicated by an arrow 145, the magnetic head slider 135 isrotated in a rolling direction also. At this time, bend deformationsoccur in the beams 131 and 132 in the respective directions opposite toeach other, and bend deformations occur in the beams 133 and 134 in therespective directions opposite to each other.

[0175]FIG. 25 shows a resonance mode of the first-order bend. Adeformation occurs in the elastic portion 123 formed at the root of thesuspension 121, and the first pair of beams 131 and 132 and the secondpair of beams 133 and 134 are deformed in the same direction.

[0176]FIG. 26 shows a resonance mode of the first-order twist. A twistdeformation occurs in the elastic portion 123 formed at the root of thesuspension 121 in such a manner so the right and left portions of theelastic portion 123 have different heights. The beam located on theright side of the gimbal 125 is deformed so as to be formed into aconvex shape facing upwards. The beam located on the left side of thegimbal 125 is deformed so as to be shaped into a convex facingdownwards. When the lengths 1₁ and 1₂ are selected so that the length 1₂is equal to three or four times the length 1₁, the rotation stiffnessresponses of the slider in the pitching and rolling directions becomesufficiently soft and are almost the same as each other.

[0177] As shown in FIG. 23, a composite type magnetic head 148 and fourterminals 1100A, 1100B, 1100C and 1100D are provided in the magnetichead slider 135. The magnetic head 148 includes an MR head forreproduction and an interactive type head for recording, these headsbeing integrated with each other. The magnetic head 148 is located at arear end surface of the magnetic head slider 135 in a relative movementdirection 146 with respect to the magnetic disk 1222.

[0178] As shown in FIGS. 27 and 28, lead wires 115A, 115B, 115C and 115Dare connected to the terminals 1100A, 1100B, 1100C and 1100D,respectively. Each of the lead wires 115A through 115D has a diameterof, for example, 30 μm. The lead wires 115A-115D are laid on the sideopposite to the side on which the magnetic head slider 135 is mounted,and are attached to a center portion 36 of the fixing portion 130 bymeans of an adhesive 116, which can be an insulation adhesive or aninsulator containing an insulator. Further, the lead wires 115A-115Dextend along the longitudinal center line 137 of the suspension 121towards the base portion of the suspension 121, and are fixed thereto attwo points by means of the adhesive 116.

[0179] Reference numbers 117 ⁻¹, 117 ⁻² and 117 ⁻³ respectively indicatea first fixing point, a second fixing point and a third fixing point atwhich the lead wires 115A through 115D are fixed by means of theadhesive 116. The first fixing point 117 ⁻¹ moves in accordance withmovement of the magnetic head slider 135. Hence, it is unnecessary to beconcerned about the stiffness of portions of lead wires 115A through115D between the terminals 1100A-1100D and the first fixing point 117 ⁻¹and to provide additional lengths of the lead wires 115A-115D. In FIG.27, such additional lengths of the lead wires 115A-115D are notprovided. The distance between the first fixing point 117 ⁻¹ and thesecond fixing point 117 ⁻² is long, and the stiffness of the lead wires115A-115B between the fixing points 117 ⁻¹ and 117 ⁻² little affects therotation stiffness of the gimbal 125.

[0180] The magnetic head suspension unit 120 has the following features.First, the rotation stiffness of the gimbal 125 is considerably smallbecause of the characteristics of the T-shaped beams. Second, the gimbal125 is supported at the four points 140-143, and hence, the resonancefrequency of vibration of the gimbal 125 is high even when the secondpair of beams 133 and 134 is long. Third, the end of the suspension 121can be formed so that it has a small width W1, and hence the resonancefrequency of vibration of the suspension 121 is high. Fourth, the flyingstability of the magnetic head slider 135 is excellent due to the abovefirst, second and third features. The fifth feature of the mechanism 120is such that the first pair of beams 131 and 132 has a short length l₁and is formed in the same plane. Hence, the first pair of beams 131 and132 has a large strength with respect to force received in the contactstart/stop operation, and a shear failure does not easily occur in thebeams 131 and 132. The sixth feature of the mechanism 120 is such thatthe stiffness of the lead wires 115A-115D does not affect the rotationstiffness of the gimbal 125.

[0181] As has been described above, the gimbal 125 is formed so that apair of T-shaped beams (which form an H-shaped beam) is provided withrespect to the center of the gimbal 125, and hence a low rotationstiffness and a high resonance frequency are achieved. Morespecifically, the rotation stiffness of the mechanism 120 becomesone-third of that of the aforementioned IBM 3380 type head suspensionunit, while the resonance frequency of the mechanism 120 is as high asthat of the IBM 3380 type head suspension unit. As a result, it becomespossible to stably fly a compact slider having a low airbearingstiffness.

[0182] Tables 1 and 2 show characteristics of the head suspension unit120 according to the fourteenth embodiment of the present inventionsupporting a 2 mm-length slider, and the IBM 3380 type head suspensionunit supporting which a 3.2 mm-length slider. TABLE 1 COMPARISON OFSTIFFNESS (static characteristics by computer simulation) Stiffness 1stembodiment 3380 type pitch stiffness 1.5 grf cm/rad 9.4 grf cm/rad rollstiffness 1.5 grf cm/rad 5.1 grf cm/rad up/down stiffness 0.55 grf/mm2.4 grf/mm equivalent weight ratio 0.74 0.72

[0183] TABLE 2 COMPARISON OF RESONANCE FREQUENCY (dynamic characteristicby computer simulation) Stiffness 1st embodiment 3380 type 1st bend 2.1kHz 2.1 kHz 1st twist 2.3 kHz 2.6 kHz in-plane 8.5 kHz 5.7 kHz

[0184] In order to make the equivalent weight ratio ((supporting springequivalent weight)/(slider weight) of the fourteenth embodiment equal tothat of the IBM 3380 type mechanism, the total length of the suspensionunit is short (10 mm), which is approximately half of that of the IBM3380 type mechanism. Further, the thickness of the suspension 121 of thefourteenth embodiment is 25 μm, which is approximately one-third of thatof the IBM 3380 type mechanism.

[0185] Table 1 shows data obtained by computer simulation. Morespecifically, Table 1 shows the pitch stiffness and roll stiffness ofthe gimbal 125 of the fourteenth embodiment, and the up/down stiffnessof the suspension 121 thereof. Further, Table 1 shows the pitchstiffness and the roll stiffness of the gimbal of the IBM 3380 typemechanism, and the up/down stiffness of the suspension thereof. It canbe seen from Table 1 that the rotation stiffness equal to one-third ofthe gimbal of the IBM 3380 type mechanism can be obtained by optimizingthe width and length of the grooves in the gimbal 125.

[0186] Table 2 shows the resonance frequencies of the fourteenthembodiment and the conventional IBM 3380 type mechanism obtained by acomputer simulation. The resonance frequencies of the fourteenthembodiment are similar to those of the IBM 3380 type mechanism.

[0187] As will be seen from the above, the magnetic head suspension unitaccording to the fourteenth embodiment of the present invention has alow stiffness and a high resonance frequency.

[0188] A description will now be given of a fifteenth embodiment of thepresent invention. In the following description, parts that are the sameas those shown in FIG. 23 are given the same reference numbers.

[0189]FIG. 29 shows a magnetic head suspension unit 150 according to thefifteenth embodiment of the present invention. The mechanism 150includes a gimbal 151. The gimbal 151 is formed so that the gimbal 125shown in FIG. 23 is rotated about the center 136 by 90°. Two T-shapedbeams 152 and 153 are arranged in the longitudinal direction of thesuspension 121.

[0190]FIG. 30 shows a magnetic head suspension unit 160 having a gimbal161 according to a sixteenth embodiment of the present invention. Thegimbal 161 has the aforementioned first pair of beams 131 and 132, and asecond pair of beams 33A and 34A. The beam 133A and the beam 131 form anacute angle α. Similarly, the beam 134A and the beam 132 form an acuteangle equal to the acute angle α. With the above structure, it becomespossible to form, without increasing the width W1 of the suspension 121,the second pair of beams 133A and 134A so that the length 2×1_(2a)thereof is greater than the length 2×1₂ of the second pair of beams 133and 134 shown in FIG. 23. Further, it is possible to narrow the end ofthe suspension 121. Hence, the rotation stiffness of the gimbal 161 isless than that of the gimbal 125 shown in FIG. 123. Thus, the magnetichead slider 135 in the sixteenth embodiment can be more stably fliedthan that in the fourteenth embodiment shown in FIG. 23.

[0191]FIG. 31 shows a magnetic head suspension unit 170 having a gimbal171 according to a seventeenth embodiment of the present invention. Amagnetic head slider 135A of the mechanism 170 includes flanges 172 and173 formed on the respective sides of the slider 35A. A magnetic headslider fixing portion 130A of the gimbal 171 includes an opening 174having a size corresponding to the magnetic head slider 135A. Theopening 174 is of a rectangular shape defined by a rectangular frame176. As shown in FIG. 31, the magnetic head slider 135A engages theopening 174, and the flanges 172 and 173 are made to adhere to the frame176 by means of an insulation adhesive or an adhesive containing aninsulator. In this manner, the magnetic head slider 135A is fixed to themagnetic head slider fixing portion 130A.

[0192] As shown in FIG. 32, the center G of gravity of the magnetic headslider 135A is substantially located on the surface of the suspension121. Hence, in a seek operation, the magnetic head slider 135A is movedby exerting a force on the center G of gravity. Thus, an unnecessaryrotation force about the center G of gravity of the magnetic head slider135A does not occur, and the unbalance of the magnetic head slider 135Ais reduced. As a result, the magnetic head slider 135A can stably fly inthe seek operation.

[0193] Further, the height of the magnetic head assembly can be reduced.Hence, it is possible to laminate layers of the head at reducedintervals and to provide an increased number of disks per unit length.As a result, it is possible to increase the volume storage density ofthe magnetic disk drive and hence the storage density.

[0194]FIG. 33 shows a magnetic head suspension unit 180 having amagnetic head slider 135B according to an eighteenth embodiment of thepresent invention. The magnetic head slider 135B has a flange 181 formedaround the circumference thereof. The magnetic head slider 135B engagesthe opening 174, and the flange 181 is adhered to the magnetic headslider fixing portion 130A by means of an adhesive which can be aninsulation adhesive or an adhesive containing an insulator. That is, theeighteenth embodiment of the present invention differs from theseventeenth embodiment thereof in that the whole circumference of themagnetic head slider 135B is made to adhere to the fixing portion 130A.Hence, the adhesive strength is increased and the reliability of themagnetic head suspension unit is improved.

[0195]FIG. 34 shows a magnetic head suspension unit 190 according to anineteenth embodiment of the present invention. FIG. 35 shows a free endof a suspension of the magnetic head suspension unit 190. The mechanism190 is designed so that it does not have any influence of the stiffnessof lead wires, which affect flying of the slider having a low airbearingstiffness. For example, when, in the case where four lead wires areconnected between the slider and the suspension (see FIG. 27), each ofthe lead wires has a diameter of 30 μm and has an additional length(free length) of 1 mm, the rotation stiffness of the gimbal isapproximately five times that of the gimbal in which there is no leadwire. This degrades the flying stability of the slider.

[0196] The magnetic head suspension unit 190 has wiring patterns 191,192, 193 and 194, which are formed by patterning a copper thin filmformed by, for example, plating by means of the photolithographytechnique. The wiring patterns 191-194 extend on a central portion ofthe lower surface of the suspension 121 in the longitudinal direction.Each of the wiring patterns 191-194 is approximately 5 μm thick and 50μm wide. The thickness and width of the wiring patterns depend on theresistance of the conductive pattern and the capacity of the suspension121.

[0197] Terminals 195A-195D made of copper are formed on the base portionof the suspension 121. Further, terminals 196A-196D are formed in aterminal area 130 a of the magnetic head slider fixing portion 130 ofthe gimbal 125. The tops of the terminals 195A-195D and 196A-196D areplated by, for example, Au. This plating contributes to preventingexposure of copper and improving the bonding performance. Ends of thewiring patterns 191, 192, 193 and 194 are respectively connected to theterminals 195A, 195B, 195C and 195D. The other ends of the two wiringpatterns 191 and 192 extend along the beams 133A and 131, and areconnected to the terminals 196A and 196B, respectively. The other endsof the wiring patterns 193 and 194 extend along the beams 134A and 132and are connected to the terminals 196C and 196D, respectively.

[0198] As shown in FIG. 36, the wiring patterns 191, 192, 193 and 194are electrically insulated from the suspension 121 by means of aninsulating film 197, and are covered by a protection film 198. Theinsulating film 197 and the protection film 198 are made ofphotosensitive polyimide and are grown to a thickness of approximately 5μm. The insulating film 197 and the protection film 198 are respectivelypatterned by the photolithography technique. The thickness of theinsulating film 197 is determined on the basis of a capacitance betweenthe conductive pattern (made of Cu) and the suspension (made ofstainless steel).

[0199] As will be described later, polyimide has heat-resistance enoughfor an annealing process. Since polyimide has photosensitivity, it canbe easily patterned. Further, the polyimide films 197 and 198 havecorrosion resistance, and excellent reliability.

[0200] It is likely that the terminals 195A-195D and 196A-196D areetched because these terminals are not covered by the protection film198. In order to prevent the terminals 195A-195D and 196A-196D frombeing etched, the surfaces of these terminals are covered by an Au film(not shown) having a thickness of approximately 1 μm formed by platingor vapor deposition.

[0201] As shown in FIG. 37, the magnetic head slider 135 is made toadhere to the fixing portion 130 by means of an adhesive which can be aninsulation adhesive or an adhesive containing an insulator. Theterminals 196A-196D are located at a right angle with respect toterminals 1100A-1100D of the magnetic head 148 formed on the end surfaceof the magnetic head slider 135, and are respectively connected to theterminals 1100A-1100D by means of Au balls 1101A-1101D. The Au balls1101A-1101D are formed by means of, for example, a gold ball bondingdevice. In order to facilitate bonding, the terminals 196A-196D andterminals 1100A-1100D are located as shown in FIG. 37. In order tofacilitate a crimp operation on the Au balls 1101A-1101D, the terminals1100A-1100D are long in the direction of the height of the magnetic headslider 135 and are located so that these terminals 1100A-1100D face theterminals 196A-196D in the state where the head slider 135 is fixed tothe fixing portion 130.

[0202] In addition to FIG. 37, FIGS. 55-59 illustrate an embodiment witha bonding ball connection in more detail.

[0203]FIG. 55 is a structural diagram of a magnetic disk apparatus towhich another embodiment of the present invention directed to bondingballs is adapted, FIG. 56 is a cross section of the structure in FIG.55, FIG. 57 is a front view of an actuator in FIG. 55, FIG. 58 is anexplanatory diagram of the seventeenth embodiment of this invention inFIG. 55, and FIG. 59 is a diagram for explaining how to connect theembodiment.

[0204]FIG. 55 illustrates a magnetic disk apparatus which allows a headto float onto a magnetic disk to execute magnetic recording.

[0205] Provided on a base 60-1 of the apparatus are a 3.5-in magneticdisk 5-1, which rotates around a spindle shaft 64-1, and a magneticcircuit 63-1. An actuator 4-1 is mounted rotatable around a rotary shaft62-1.

[0206] A coil 41-1 is provided at the rear portion of this actuator 4-1,as shown in FIGS. 59, 56 and 57, and the coil 41-1 is located in themagnetic circuit 63-1.

[0207] As shown in FIG. 56, nine arms 3-1 are formed at the frontportion of the actuator 4-1, each arm 3-1 are formed at the frontportion of the actuator 4-1, each arm 3-1 provided with support plate(suspension) 7-1 which has a magnetic head core (core slider) 8-1provided at the distal end.

[0208] This actuator 4-1, together with the coil 41-1 and magneticcircuit 63-1, form a linear actuator. When current flow through the coil41-1, the actuator 4-1 rotates around the rotary shalt 62-1 to move themagnetic head core 8-1 for a seek operation in a direction perpendicularto the tracks of the magnetic disk 5-1 (radial direction).

[0209] In FIG. 58, “7-1” is a support plate (suspension) made of metalhaving a spring property, such as stainless. An insulating layer iscoated on the support plate, and a pair of wiring patterns 71-1 andsuspension connector terminals 72-1 are formed thereon by a copperpattern. The support plate 7-1 has its one end fixed to the arm 3-1 bylaser spot welding or the like.

[0210] “8-1” is a magnetic head core (core slider) which has a pair ofcore slider connector terminals 82-1 and a thin-film magnetic head 81-1provided on the sides.

[0211] When the magnetic head core 8-1 is mounted on the support plate7-1, the connector terminals 72-1 of the support plate 7-1 and theconnector terminals 82-1 of the magnetic head core 8-1 are fixed withthe positional relationship as shown in FIG. 58(B) and 59(A), and goldballs W about 0.1 mm in diameter are made to contact both gold-platedconnector terminals 82-1 and 72-1 and are subjected to pressure bondingan ultrasonic bonding by a ball bonder, the connector terminals 82-1 and72-1 are electrically and mechanically connected via the gold balls Wdue to intermetal bonding. In this example, the magnetic disk 5-1 islocated upward of the diagram.

[0212] When the support plate 7-1 is provided with the wiring patterns71-1 and connector terminals 72-1 while the magnetic head core 8-1 isprovided with eh connector terminals 82-1, they can be connected by goldball bonding. Therefor, even the minute magnetic head core 8 can easilybe connected, thus accomplishing the miniaturization of the magnetichead assembly.

[0213] Further, unlike lead wires, wiring is not necessary, so thatdifficult wiring at the minute suspension is unnecessary, furtherfacilitating the assembling.

[0214] Furthermore, the number of components is reduced to make theassembling easier and accomplish a small magnetic head assembly.

[0215]FIG. 59(b) shows a modification of the seventeenth embodiment inwhich a dummy terminal 83-1 is provided at the flow-in side of themagnetic head core 8-1, and a dummy terminal 73-1 is provided on thewiring pattern 71-1 of the support plate 7-1 accordingly. With goldballs W about 0.1 mm in diameter in contact with both gold-platedconnector terminals 83-1 and 73-1, pressure bonding and ultrasonicbonding are performed by a ball bonder, those connector terminals 83-1and 73-1 are connected together via the gold balls W due to intermetalbonding.

[0216] Accordingly, the magnetic head core 8-1 has both ends connectedby the gold balls W to the support plate 7-1, so that adhesion of themagnetic head core 8-1 to the support plate 7-1 is unnecessary and theconnection can be made by the ball bonding step alone, furtherfacilitating the assembly.

[0217] Although the lead wires are connected to the arm side terminals(see FIG. 58(A)) of the wiring patterns 71-1 of the support plate 7-1before connecting to the arm 3-1 in this example, this wiring is easybecause the arm 3-1 is relatively large.

[0218] The wiring patterns 191-194 bypass holes 1102A, 1102B and 1102C,as shown in FIG. 34 and extend up to an area close to the head slider135. The hole 1102 c is used to fix the suspension 121 to the arm 122(not shown in FIG. 34). The holes 1102A, 110B and 1102C are sized suchthat a tool can be inserted therein.

[0219] As shown in FIGS. 34 and 35, dummy patterns 1103A-1103D and1104A-1104D are provided so that these dummy patterns are symmetrical tothe bypassing portions of the wiring patterns 191-194 with respect tothe holes 1102A and 1102B. The insulating film 197 and the protectionfilm 198 are provided for the dummy patterns 1103A-1103D and 1104A-1104Din the same manner as the wiring patterns 191-194. The dummy patterns1103A-1103D and 1104A-1104D are provided in order to balance themechanical stiffness of the suspension 121 in the direction of the widthof the suspension 121.

[0220] As shown in FIG. 35, the wiring patterns 191-194 are arranged sothat these patterns form a loop. This loop functions as an antenna,which receives noise components contained in the head signals. As thesize of the loop is increased, the degree of the noise components isincreased. In order to reduce the size of the loop, the wiring patterns191 and 192 respectively connected to the terminals 196A and 196B arearranged between the hole 1102A and the magnetic head slider 135, andall the wiring patterns 191-194 are gathered in the vicinity of the hole1102A. In order to balance the stiffness in the direction of the widthof the suspension, the dummy patterns 1104A-1104D are formed. For thesame reason as above, the dummy patterns 1103A-1103D are formed in thevicinity of the hole 1102B.

[0221] As shown in FIG. 35, auxiliary films 1106 and 1107 having a beltshape are formed along the right and left ends of the suspension 121.The auxiliary films 1106 and 1107 are provided in order to receive aclamping force generated when the suspension 121 is clamped in a bendingprocess which will be described later. Such a clamping force is alsoreceived by the wiring patterns 191-194. The clamping force isdistributed so that the clamping force is exerted on not only the wiringpatterns 191-194 but also the auxiliary films 1106 and 1107. Hence, itis possible to prevent the wiring patterns 191-194 from being damaged.

[0222] As shown in FIGS. 34 and 35, a convex dummy pattern 1108 isprovided in order to prevent an adhesive from flowing from the fixingportion 130 when the slider 135 is fixed to the fixing portion 130 andto prevent the slider 135 from being tilted due to the thickness of thewiring patterns. More particularly, the convex pattern 1108 is used toform a groove in which an insulation adhesive used to fix the slider 135is saved between the pattern 1108 and the terminals 196A-196D. Further,the convex pattern 1108 is designed to have the same height as thepatterns having the terminals 196A-196D. If the dummy pattern 1108 isnot used, the slider 135 will be inclined with respect to the fixingportion 130 due to the height of the terminals 194A-194D. This degradesthe flying stability of the heads. Further, the use of the convex dummypattern 1108 increases the height of the adhesive to thus improve theinsulation performance. The convex pattern 1108 can be formed by acooper-plated thin film similar to the wiring patterns 191-194. Theprotection film 198 covers the convex pattern 1108. The adhesive isprovided on a step part between the wiring patterns and the convexpattern 1108.

[0223] The suspension 121 is produced by a process shown in FIG. 38.First, a pattern formation step 1110 is performed. More particularly,photosensitive polyimide is coated on a stainless plate. The insulatingfilm 197 is formed by the photolithography technique. A copper film isformed by the plating process, the vapor deposition process or the like,and is patterned into the wiring patterns 191-194 by thephotolithography technique. Thereafter, photosensitive polyimide iscoated and is patterned into the protection film 198 and the auxiliaryfilms 1106 and 1107 by the photolithography technique. Polyimide can becoated by a spin-coat process, and is patterned and etched. A thin film,such as a Cr film, can be formed in order to improve the adhesivenessbetween the insulating film and the Cu film and between the Cu film andthe protection film and to improve the reliability of the adhesion.

[0224] Next, an etching step 111 is performed in order to form theopenings 126-129 and the holes 1102A-1102C and the outward form of thesuspension in the stainless plate. FIG. 39 shows suspensions 1202 beforepunching for cutting off bridge portions (not shown) to provide pieces,so that the suspensions 1202 are formed in a stainless plate 1201 andarranged in rows and columns.

[0225] Then, a bending step 1112 is performed by bending the respectiveends of each of the suspensions 1202 formed in the stainless plate 1201,so that ribs 121 a are formed. The bending step 1112 can be performed bypress so that the suspensions 1202 are processed at the same time.

[0226] Finally, an annealing step 1113 is performed at a temperature ofapproximately 400° C., so that internal stress can be removed. Further,a slider adhering step and an Au bonding step can be automaticallycarried out before the suspensions 1202 are punched. Hence, it ispossible to automatically perform the production process shown in FIG.38 and reduce the number of steps and the cost thereof.

[0227] The suspension 121 can be produced without performing theannealing step 1113. In this case, as is shown in FIG. 40, the patternformation step 1110 and the etching step 1111 are performed, andsubsequently the slider adhering step and the Au bonding step arecarried out. Thereafter, the bending step 1112 is carried out to formthe ribs 121 a.

[0228] As shown in FIG. 41, when interactive type heads 148A and 148Bfor recording and reproduction are used as magnetic heads, the magnetichead slider 135 has the aforementioned two terminals 1100A and 1100B. Inthe gimbal 125, the two wiring patterns 191A and 192A are provided sothat these wiring patterns extend on only the beams 132 and 134A, whiletwo dummy patterns 1210 and 1211 are provided so as to extend on thebeam 131 and 133A in order to balance the mechanical stiffness of thesuspension 121 in the direction of the width of the suspension 121.

[0229] The magnetic head suspension unit 190 has the following features.

[0230] First, since the wiring patterns 191-194 are formed on thesuspension 121, it is not necessary to provide tubes for passing thelead wires through the suspension 121. Hence, it is possible to preventunbalanced force caused by the lead wires and tubes from being exertedon the magnetic head slider 135 and to stably fly the magnetic headslider 135.

[0231] Second, due to use of the dummy patterns 1103A-1103D and1104A-1104D, the rotation stiffness of the suspension 121 does not havepolarity. Hence, the magnetic head slider can fly stably.

[0232] Third, the crimp connection using the Au balls 1101A-1101Denables automatic assembly and non-wire bonding between head terminalsand pattern terminals.

[0233] In the aforementioned embodiments of the present invention, thebeams may be curved.

[0234] A description will now be given of a magnetic head suspensionunit suitable for a more compact magnetic disk drive according to atwelfth embodiment of the present invention.

[0235]FIG. 42 shows a back surface of a magnetic head suspension unit1230 according to the twelfth embodiment of the present invention. FIG.43 shows a 1.8-inch-type magnetic disk drive 1231 to which the magnetichead suspension unit 1230 is applied.

[0236] The magnetic disk drive 1231 has an enclosure 1232 having almostthe same dimensions as those of an IC memory card. In the enclosure1232, provided are a magnetic disk 1233 having a diameter of 1.8 inches,and an actuator to which two sets of magnetic head suspension units areattached. The magnetic disk drive 1231 is more compact than the magneticdisk drive 1220 shown in FIG. 3.

[0237] A magnetic head slider 135C is made compact in accordance withlight-sizing of the magnetic disk drive 1231. More particularly,dimensions a×b of the magnetic head slider 135C are 0.8 mm×1.0 mm, andare approximately one-quarter the area of the magnetic head slider 135shown in FIG. 23. In order to stably fly the compact magnetic headslider 135C, it is necessary to considerably reduce the stiffnesswithout decreasing the resonance frequency, as compared with themagnetic head suspension unit 130.

[0238] A suspension 1235 shown in FIG. 42 is made of stainless, and hasa base portion fixed to an arm 1236 of the actuator 1234 (see FIG. 43).The suspension 1235 has a width W2 of approximately 2 mm, a length L ofapproximately 9 mm, and a thickness to of approximately 25 μm, and isapproximately a half of the volume of the suspension 121 shown in FIG.23. The suspension 1235 is diminished, and hence the resonance frequencyof bending which will be described later is high.

[0239] The suspension 1235 is a sheet-shaped piece, and a flat platepiece to which a bending process has not been subjected. Hence, there isno problem of a bending process error which degrades the flyingstability of the magnetic head slider. The suspension 1235 includes asuspension main body 1237 and a gimbal 1238 located on the end side ofthe suspension 1235. The gimbal 1238 has a substantially U-shapedopening (through hole) 1239 formed in the suspension 1235. The gimbal1238 includes a magnetic head slider fixing portion 1240, a first beam1241, a second beam 1242, a third beam 1244, and a connecting portion1243.

[0240] The magnetic head slider fixing portion 1240 has a sizecorresponding to the magnetic head slider 135C. The first beam 1241 andthe second beam 1242 extend along respective longitudinal ends of thesuspension 1235 from the end thereof. The connecting portion 1243extends in the direction of the width of the suspension 1235, andconnects the first beam 1241 and the second beam 1242 together. Thethird beam 1244 extends from the connecting portion 1243 to the magnetichead slider fixing portion 1240 in the longitudinal direction of thesuspension 1235. The magnetic head slider fixing portion 1240 isconnected to the main body 1237 of the suspension 1235 via the thirdbeam 1244, the connecting portion 1243 and the first and second beams1241 and 1242. Hence, the rotation stiffness of the suspension 1230 canbe reduced to a small value due to bending of the entire beams.

[0241] As shown in FIG. 42, holes 1245, 1246 and 1247 with which a toolis engaged, and a pair of slits 1248 and 1249 are formed in the mainbody 1237 of the suspension 1235. Adjustment slits 1248 and 1249 areused to reduce the rotation stiffness of the suspension. The holes 1245,1246 and 1247 and the slits 1248 and 1249 are formed by etching. Theconnectors 195A-195D, 196A-196D and the wiring patterns 191-194 areformed symmetrically with respect to the longitudinal direction of thesuspension 1235. The magnetic head slider 135C is made to adhere to thefixing portion 1240, and the terminals 196A-196D and 1100A-1100D arerespectively connected to each other by means of Au balls, as in thecase shown in FIG. 37.

[0242] The structure shown in FIG. 42 does not use dummy patternsbecause the length and the width of the suspension 1235 are less thanthose of the suspension shown in FIG. 34 and the loop formed by thewiring patterns is smaller than that shown in FIG. 34. However, it ispreferable to arrange the wiring patterns and provide the dummy patternsas shown in FIGS. 34 and 35 in order to reduce the noise from the heads.

[0243] As shown in FIGS. 44A and 44B, the free end of the arm 1236 isbent so that a substantially V-shaped cross section of the arm 1236 isformed in which the “V” is inverted. The free end of the arm 1236 has anupward slant portion 1236 a and a downward slant portion 1236 b declinedat an angle θ with respect to the horizontal direction.

[0244] The magnetic disk drive 1231 uses two magnetic head suspensionunits 1230 so that the single magnetic disk 1233 is sandwiched betweenthe mechanisms 1230. As shown in FIG. 45, the suspension 1235 causes themagnetic head slider 135C to come into contact with the magnetic disk1233 when the magnetic disk 1233 is not being rotated. At this time, themain body 1237 of the suspension 1235 is caused to be bent andelastically deformed. The elastic force stored in the main body 1237 ofthe suspension 1235 generates a load F1, which urges the magnetic headslider 35C towards the magnetic disk 1233.

[0245] Since the arm 1236 is bent in the form of the inverted “V”, awide gap 1250 can be formed between an end 1236 c of the arm 1236 andthe magnetic disk 1233, as compared with a case indicated by a two-dotchained line in which the arm 1236 is simply bent downwards.

[0246] A description will now be given of a moment exerted on themagnetic head slider 135C by means of the suspension 1235 when thesuspension is loaded on the disk. As shown in FIG. 46, the main body1237 of the suspension 1235 and the third beam 1244 are bent. Hence, amoment is exerted by a center 1251 of the magnetic head slider 35C. Amoment M1 directed counterclockwise is exerted by the suspension mainbody 1237 and the first and second beams 1241 and 1242. A moment M2directed clockwise is exerted on the third beam 1244. The dimensions ofthe suspension 1235 are selected so that the moments M1 and M2 arebalanced. For example, the suspension 1235 is 9 mm long, and the gimbal1238 is 2.5 mm long. Further, the length and width of the main body 1235of the suspension 1237 are 5.7 mm and 2 mm, respectively. With the abovestructure, it is possible to stably fly the magnetic head slider 135C.

[0247] A description will now be given, with reference to FIG. 42, ofpitching and rolling of the magnetic head slider 135C.

[0248] (1) Pitching

[0249] The magnetic head slider 135C is rotated in the pitchingdirection indicated by arrow 144 in such a manner that the first, secondand third beams 1241, 1242 and 1244 and the suspension main body 1237are bent. At this time, all the beams 1241, 1242 and 1244 are bent so asto be deformed in the form of arch shapes. The gimbal 1238 is bent andhence the suspension main body 1237 is bent. Hence, the pitch stiffnesscan be greatly reduced.

[0250] (2) Rolling

[0251] The magnetic head slider 135C is rotated in the rolling directionindicated by arrow 145 in such a manner that the first and second beams1241 and 1242 are respectively bent in the opposite directions and thesuspension main body 1237 is twisted. At this time, the gimbal 1238 isbent and hence the suspension main body 1237 is bent. Hence, the rollingstiffness can be greatly reduced.

[0252] A description will now be given of the first-order bend and thefirst-order twist of the magnetic head suspension unit 1230 obtainedwhen the suspension is vibrated.

[0253] (1) First-order bend

[0254] The suspension 1235 is bent and deformed, as shown in FIG. 47.More specifically, the suspension main body 1237, and the first, secondand third beams 1241, 1242 and 1244 of the gimbal 1238 are bent as shownin FIG. 45. The overall suspension 1235 is formed flexibly, but theresonance frequency of the first-order bend is high, while the stiffnessis small.

[0255] (2) First-order twist

[0256] The suspension 1235 is twisted as shown in FIG. 48. The gimbal1238 is deformed and hence the suspension m body 1237 is deformed.Hence, the overall suspension 1235 is flexibly formed, but the resonancefrequency of the first-order twist is high while the stiffness thereofis low.

[0257] Tables 3 and 4 show characteristics of the magnetic head supportmechanism 1230 according to the twelfth embodiment of the presentinvention and the magnetic head suspension unit 130 of the fourteenthembodiment thereof shown in FIG. 23. TABLE 3 COMPARISON OF STIFFNESS(static characteristics by computer simulation) Stiffness 7th embodiment1st embodiment pitch stiffness 0.44 grf cm/rad 1.5 grf cm/rad rollstiffness 0.24 grf cm/rad 1.5 grf cm/rad up/down stiffness 0.36 grf/mm0.55 grf/mm equivalent weight ratio 0.76 0.74

[0258] TABLE 4 COMPARISON OF RESONANCE FREQUENCY (dynamiccharacteristics by computer simulation) Stiffness 7th embodiment 1stembodiment 1st bend 1.6 kHz 2.1 kHz 1st twist 4.4 kHz 2.3 kHz in-plane7.1 kHz 8.5 kHz

[0259] More particularly, Table 3 the pitch stiffness, the rollstiffness, and the up/down stiffness of the suspension 1235 obtained bymeans of a computer simulation. It can be from Table 3 that the pitchstiffness and the roll stiffness of the twelfth embodiment of thepresent invention are approximately one-quarter of those of thefourteenth embodiment thereof.

[0260] Table 4 shows the resonance frequencies of the fourteenth andtwelfth embodiments of the present invention obtained by a computersimulation. It can be seen from Table 4 that the first-order bendresonance frequency, the first-order twist resonance frequency and thelateral resonance frequency are kept very high.

[0261] It can be seen from Tables 3 and 4 that the magnetic headsuspension unit 1230 according to the twelfth embodiment of the presentinvention has a resonance frequency as high as that of the magnetic headsuspension unit 130 according to the fourteenth embodiment, andstiffness much less than that of the mechanism 130. Hence, the compactmagnetic head slider 135C can be stably flied.

[0262] In an alternative of the suspension, the base portion of thesuspension 1237 is bent, so that the suspension is supported in the samemanner as shown in FIG. 23 and the load F1 shown in FIG. 45 is obtained.In this case, only portions 1255 and 1256 outside of the slits 1248 and1249 are bent. Hence, unnecessary strain is not exerted on the wiringpatterns 191-194 located between the slits 1248 and 1249.

[0263] A first variation of the gimbal 1238 of the suspension 1235 willbe described. A gimbal 1238 ⁻¹ shown in FIG. 49 has a first beam 1244 ⁻¹having a long width A, and an opening 1239 ⁻¹ having a long length B.First and second beams 1241 ⁻¹ and 1242 ⁻¹ are long.

[0264]FIG. 50 shows a second variation 1238 ⁻² of the gimbal 1238. Thegimbal 1238 ⁻² has first and second beams 1241 ⁻² and 1242 ⁻² eachhaving a small width C.

[0265]FIG. 51 shows a third variation 1238 ⁻³ of the gimbal 1238. Thegimbal 1238 ⁻³ has first and second variations 1241 ⁻³ and 1242 ⁻³having a large width D.

[0266]FIG. 52 shows a fourth variation 1238 ⁻⁴ of the gimbal 1238. Thegimbal 1238 ⁻⁴ has a fourth beam 1260 connecting the center of the endof the magnetic head slider fixing portion 1240 and the suspension mainbody 1237 together. The fourth beam 1260 functions to prevent adeformation of the magnetic head slider fixing portion 1240, butincreases the rotation stiffness. Hence, it is desired that the width ofthe fourth beam 1260 be as small as possible and the length thereof areas long as possible.

[0267]FIG. 53 shows a fifth variation 1238 ⁻⁵ of the gimbal 1238. Thegimbal 1238 ⁻⁵ has first and second arch-shaped beams 1241 ⁻⁵ and 1242⁻⁵.

[0268] As shown in FIG. 54, a bent connecting plate 1261 is fixed to anarm 1236A, and the suspension 1235 is fixed to the connecting plate1261. Hence, it is not necessary to subject the arm 1236A to bendingstresses.

[0269] In the variations shown in FIG. 49 through 132, it can be saidthat the third beam 1244 shown in FIG. 42 has the same width as thefixing portion 1240 and is integrated with the fixing portion 1240.

[0270] In the fourteenth through nineteenth embodiments, the loadapplied to the magnetic head slider is generated by bending the springportion of the suspension. Alternatively, it is possible to employ thearm fixing structure used in the twelfth embodiment of the presentinvention in which the spring portion is kept flat.

[0271] The present invention is not limited to the specificallydisclosed embodiments and variations, and other variations andmodifications may be made without departing from the scope of thepresent invention.

What is claimed is:
 1. A method for assembling a recording/reproducinghead assembly which comprises a slider and a slider supporting member,the slider having a head element and a head terminal connected to thehead element, said method comprising the steps of: forming on the slidersupporting member a terminal to be connected to the head terminal;fixing the head slider on the slider supporting member so that the headterminal faces the terminal of the slider supporting member; contactinga conductive ball member to both of the head terminal and the terminalof the slider supporting member; and pressing the ball member to bondthe head terminal and the terminal of the slider supporting member,whereby the ball member electrically and mechanically connects bothterminals.
 2. The method as claimed in claim 1 , wherein both theterminals face at right angles to each other.
 3. The method as claimedin claim 1 , further comprising a step of irradiating ultrasonic wavesduring pressing the ball member.
 4. The method as claimed in claim 1 ,wherein the ball member is made of gold.
 5. The method as claimed inclaim 1 , further comprising a step of plating both the terminals withgold before contacting the ball member.
 6. The method as claimed inclaim 5 wherein the ball is made of gold.
 7. The method as claimed inclaim 6 , further comprising a radiating ultrasonic waves duringpressing the ball member.